Polyester resins such as polyethylene terephthalate resin have excellent mechanical strength, rigidity, heat resistance, chemical resistance, oil resistance and transparency. Utilizing these excellent properties, the polyester resins are widely used for forming packaging materials such as films, sheets and containers. The polyester resins, however, have high permeability to gases such as oxygen, and therefore they cannot be used for forming packaging materials requiring high resistance to gas permeation, e.g., those for foods, medicaments and cosmetics.
Also, polycarbonate resins have excellent transparency, heat resistance and retention of scent, but they have high permeability to gases such as oxygen. Therefore, the polycarbonate resins cannot be used for forming packaging materials requiring high resistance to gas permeation, e.g., those for foods.
To improve the gas permeation resistance of the polyester resins and the polycarbonate resins, it has been proposed that a resin superior to the polyester resins and the polycarbonate resins in the gas permeation resistance, such as a saponified ethylene/vinyl acetate copolymer resin, is laminated on those resins. However, the adhesive strength between the polyester or polyester resin and the saponified ethylene/vinyl acetate copolymer resin is not always satisfactory, and this results in such a problem that partial separation takes place when the resins are laminated or the resulting laminate is used, whereby gas permeation resistance is decreased and appearance or mechanical strength of the final product is deteriorated.
To cope with the problem, Japanese Patent Laid-Open Publications No. 270155/1986 and No. 158043/1987 disclose laminates comprising a polycarbonate or polyester layer, an intermediate adhesive layer formed from an ethylene/.alpha.-olefin random copolymer having been graft-modified with an unsaturated carboxylic acid or its derivative and a saponified ethylene/vinyl acetate copolymer layer. The laminates not only show high gas permeation resistance but also have excellent adhesion properties at ordinary temperature, but when the laminates are subjected to high-temperature treatment such as hot filling treatment or retorting treatment, the adhesive strength may be decreased to cause separation of layers, resulting in lowering of gas permeation resistance.
Japanese Patent Laid-Open Publication No. 45445/1989 (correspond to U.S. Pat. No. 5,055,526, EP 315418B) applied by the present applicant discloses an adhesive resin composition capable of forming a laminate which is free from lowering of adhesive strength between the layers even after it is subjected to high-temperature treatment such as hot filling treatment or retorting treatment, and also discloses a laminate using the composition.
This adhesive resin composition comprises:
(a) an ethylene/.alpha.-olefin copolymer having a melt flow rate of 0.1 to 50 g/10 min, a density of 0.850 to 0.900 g/cM.sup.3, an ethylene content of 75 to 95% by mol and a crystallinity (measured by X-ray diffractometry) of less than 30%, in an amount of 95 to 50% by weight, PA1 (b) an ethylene/vinyl acetate copolymer having a melt flow rate of 0.1 to 50 g/10 min and a vinyl acetate content of 5 to 40% by weight, in an amount of 5 to 50% by weight, and PA1 (c) a partially or wholly graft-modified ethylene/aromatic vinyl compound copolymer having a graft quantity of an unsaturated carboxylic acid or its derivative ranging from 0.05 to 15% by weight, a melt flow rate of 0.1 to 50 g/10 min, a density of 0.900 to 0.980 g/cm.sup.3 and a crystallinity (measured by X-ray diffractometry) of not less than 30%, in an amount of 1.0 to 30% by weight based on 100% by weight of the total amount of the components (a) and (b), PA1 said composition having a graft ratio of 0.01 to 3% by weight, a melt flow rate (MFR) of 0.1 to 50 g/10 min and a crystallinity of less than 35%. PA1 (A) a partially or wholly graft-modified .alpha.-olefin/aromatic vinyl compound random copolymer having a graft quantity of an unsaturated carboxylic acid or its derivative ranging from 0.01 to 30% by weight, in an amount of 1 to 80 parts by weight, and PA1 (B) at least one soft polymer selected from an ethylene/.alpha.-olefin copolymer, in which the molar ratio of constituent units derived from ethylene to constituent units derived from an .alpha.-olefin of 3 to 20 carbon atoms is in the range of 45/55 (ethylene/.alpha.-olefin) to 95/5, and an ethylene/vinyl acetate copolymer having a vinyl acetate content of 5 to 40% by weight, in an amount of 20 to 99 parts by weight, PA1 the total amount of said components (A) and (B) being 100 parts by weight. PA1 (I) a polyester resin layer, PA1 (II) an adhesive layer formed from the above-mentioned adhesive resin composition, and PA1 (III) a saponified olefin/vinyl acetate copolymer layer. PA1 (I) a polycarbonate layer, PA1 (II) an adhesive layer formed from the above-mentioned adhesive resin composition, and PA1 (III) a saponified olefin/vinyl acetate copolymer layer. PA1 the total amount of the constituent units derived from ethylene and the constituent units derived from the .alpha.-olefin of 3 to 20 carbon atoms is in the range of 99.95 to 70% by mol, preferably 99.90 to 80% by mol, more preferably 99.00 to 88% by mol; and PA1 the amount of the constituent units derived from the aromatic vinyl compound is in the range of 0.05 to 30% by mol, preferably 0.10 to 20% by mol, more preferably 0.10 to 12% by mol. PA1 alkyl groups, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl, pentyl, hexyl, octyl, decyl and dodecyl; PA1 cycloalkyl groups, such as cyclopentyl and cyclohexyl; PA1 aryl groups, such as phenyl and tolyl; and PA1 aralkyl group, such as benzyl and neophyl. PA1 rac-dimethylmethylene-bis(indenyl)zirconium dichloride, PA1 rac-dimethylmethylene-bis(2-methyl-1-indenyl)zirconium dichloride, PA1 rac-diphenylmethylene-bis(2-methyl-1-indenyl)zirconium dichloride, PA1 rac-ethylene-bis(2-methyl-1-indenyl)zirconium dichloride, PA1 rac-dimethylsilylene-bis(2-methyl-1-indenyl)zirconium dichloride, PA1 rac-dimethylsilylene-bis(2-methyl-1-indenyl)zirconium dimethyl, PA1 rac-ethylene-bis(2-methyl-1-indenyl)zirconium dimethyl, PA1 rac-phenyl(methyl)silylene-bis(2-methyl-1-indenyl)zirconium dichloride, PA1 rac-diphenyl-silylene-bis(2-methyl-1-indenyl)zirconium dichloride, PA1 rac-methylethylene-bis(2-methyl-1-indenyl)zirconium dichloride, and PA1 rac-dimethylsilylene-bis(2-ethyl-1-indenyl)zirconium dichloride. PA1 silyl ethers of hydrocarbon-substituted silyls, such as trimethylsilyl ether; PA1 silicon-substituted alkyl groups, such as trimethylsilylmethyl; and PA1 silicon-substituted aryl groups, such as trimethylsililphenyl. PA1 rac-Dimethylsilylene-bis(4,7-dimethyl-1-indenyl)zirconium dichloride, PA1 rac-Dimethylsilylene-bis (2,4, 7-trimethyl-1-indenyl) zirconium dichloride, PA1 rac-Dimethylsilylene-bis(2,4,6-trimethyl-1-indenyl)zirconium dichloride, PA1 rac-Dimethylsilylene-bis(2,5,6-trimethyl-1-indenyl)zirconium dichloride, PA1 rac-Dimethylsilylene-bis(2,4,5, 6-tetramethyl-1-indenyl)zirconium dichloride, PA1 rac-Dimethylsilylene-bis(2,4,5,6,7-pentamethyl-1-indenyl)zirconium dichloride, PA1 rac-Dimethylsilylene-bis(2-methyl-4-n-propyl-7-methyl-1-indenyl)zirconium dichloride, PA1 rac-Dimethylsilylene-bis(4-4--propyl-7-methyl-1-indenyl)zirconium dichloride, PA1 rac-Dimethylsilylene-bis(2-methyl-4-i-propyl-7-methyl-1-indenyl)zirconium dichloride, PA1 rac-Dimethylsilylene-bis(2-methyl-4-i-propyl-6-methyl-1-indenyl)zirconium dichloride, PA1 rac-Dimethylsilylene-bis(2-methyl-4-methyl-6-i-propyl-1-indenyl)zirconium dichloride, PA1 rac-Dimethylsilylene-bis(2-methyl-4-i-propyl-5-methyl-1-indenyl)zirconium dichloride, PA1 rac-Dimethylsilylene-bis(2-methyl-4,6-di(i-propyl)-1-indenyl)zirconium dichloride, PA1 rac-Dimethylsilylene-bis(2-methyl-4,6-di(i-propyl)-7-methyl-1-indenyl)zirco nium dichloride, PA1 rac-Dimethylsilylene-bis(2-methyl-4-i-butyl-7-methyl-1-indenyl)zirconium dichloride, PA1 rac-Dimethylsilylene-bis(2-methyl-4-sec-butyl-7-methyl-1-indenyl)zirconium dichloride, PA1 rac-Dimethylsilylene-bis(2-methyl-4,6-di(sec-butyl)-1-indenyl)zirconium dichloride, PA1 rac-Dimethylsilylene-bis(2-methyl-4-tert-butyl-7-methyl-1-indenyl)zirconium dichloride, PA1 rac-Dimethylsilylene-bis(2-methyl-4-cyclohexyl-7-methyl-1-indenyl)zirconium dichloride, PA1 rac-Dimethylsilylene-bis(2-methyl-4-benzyl-7-methyl-1-indenyl)zirconium dichloride, PA1 rac-Dimethylsilylene-bis(2-methyl-4-phenylethyl-7-methyl-1-indenyl)zirconiu m dichloride, PA1 rac-Dimethylsilylene-bis(2-methyl-4-phenyldichloromethyl-7-methyl-1-indenyl )zirconium dichloride, PA1 rac-Dimethylsilylene-bis(2-methyl-4-chloromethyl-7-methyl-1-indenyl)zirconi um dichloride, PA1 rac-Dimethylsilylene-bis(2-methyl-4-trimethylsilylmethyl-7-methyl-l-indenyl )zirconium dichloride, PA1 rac-Dimethylsilylene-bis(2-methyl-4-trimethylsiloxymethyl-7-methyl-1-indeny l)zirconium dichloride, PA1 rac-Diethylsilylene-bis(2-methyl-4-i-propyl-7-methyl-1-indenyl)zirconium dichloride, PA1 rac-Di(i-propyl)silylene-bis(2-methyl-4-i-propyl-7-methyl-1-indenyl)zirconi um dichloride, PA1 rac-Di(n-butyl)silylene-bis(2-methyl-4-i-propyl-7-methyl-1-indenyl)zirconiu m dichloride, PA1 rac-Di(cyclohexyl)silylene-bis(2-methyl-4-i-propyl-7-methyl-1-indenyl)zirco nium dichloride, PA1 rac-Methylphenylsilylene-bis(2-methyl-4-i-propyl-7-methyl-1-indenyl)zirconi um dichloride, PA1 rac-Diphenylsilylene-bis(2-methyl-4-i-propyl-7-methyl-1-indenyl)zirconium dichloride, PA1 rac-Diphenylsilylene-bis(2-methyl-4-di(i-propyl)-1-indenyl)zirconium dichloride, PA1 rac-Di(p-tolyl)silylene-bis(2-methyl-4-i-propyl-7-methyl-1-indenyl)zirconiu m dichloride, PA1 rac-Di(p-chlorophenyl)silylene-bis(2-methyl-4-i-propyl-7-methyl-1-indenyl)z irconium dichloride, PA1 rac-Dimethylsilylene-bis(2-methyl-4-i-propyl-7-methyl-1-indenyl)zirconium dibromide, PA1 rac-Dimethylsilylene-bis(2-methyl-4-i-propyl-7-methyl-1-indenyl)zirconium dimethyl, PA1 rac-Dimethylsilylene-bis(2-methyl-4-i-propyl-7-methyl-1-indenyl)zirconium methylchloride, PA1 rac-Dimethylsilylene-bis(2-methyl-4-i-propyl-7-methyl-1-indenyl) zirconium-bis(methanesulfonato), PA1 rac-Dimethylsilylene-bis(2-methyl-4-i-propyl-7-methyl-1-indenyl) zirconium-bis(p-phenylsulfinato), PA1 rac-Dimethylsilylene-bis(2-methyl-3-methyl-4-i-propyl-6-methyl-1-indenyl)zi rconium dichloride, PA1 rac-Dimethylsilylene-bis(2-ethyl-4-i-propyl-6-methyl-1-indenyl)zirconium dichloride, and PA1 rac-Dimethylsilylene-bis(2-phenyl-4-i-propyl-6-methyl-1-indenyl)zirconium dichloride. PA1 rac-Dimethylsilylene-bis(4-phenyl-1-indenyl)zirconium dichloride, PA1 rac-Dimethylsilylene-bis(2-methyl-4-phenyl-1-indenyl)zirconium dichloride, PA1 rac-Dimethylsilylene-bis(2-methyl-4-(.alpha.-naphthyl)-1-indenyl)zirconium dichloride, PA1 rac-Dimethylsilylene-bis(2-methyl-4-(.beta.-naphthyl)-1-indenyl)zirconium dichloride, PA1 rac-Dimethylsilylene-bis(2-methyl-4-(1-anthracenyl)-1-indenyl)zirconium dichloride, PA1 rac-Dimethylsilylene-bis(2-methyl-4-(2-anthracenyl)-1-indenyl)zirconium dichloride, PA1 rac-Dimethylsilylene-bis(2-methyl-4-(9-anthracenyl)-1-indenyl)zirconium dichloride, PA1 rac-Dimethylsilylene-bis(2-methyl-4-(9-phenanthryl)-1-indenyl)zirconium dichloride, PA1 rac-Dimethylsilylene-bis(2-methyl-4-(p-fluorophenyl)-1-indenyl)zirconium dichloride, PA1 rac-Dimethylsilylene-bis(2-methyl-4-(pentafluorophenyl)-1-indenyl)zirconium dichloride, PA1 rac-Dimethylsilylene-bis(2-methyl-4-(p-chlorophenyl)-1-indenyl)zirconium dichloride, PA1 rac-Dimethylsilylene-bis(2-methyl-4-(m-chlorophenyl)-1-indenyl)zirconium dichloride, PA1 rac-Dimethylsilylene-bis(2-methyl-4-(p-chlorophenyl)-1-indenyl)zirconium dichloride, PA1 rac-Dimethylsilylene-bis(2-methyl-4-(o,p-dichlorophenyl)phenyl-1-indenyl)zi rconium dichloride, PA1 rac-Dimethylsilylene-bis(2-methyl-4-(p-bromophenyl)-1-indenyl)zirconium dichloride, PA1 rac-Dimethylsilylene-bis(2-methyl-4-(p-tolyl)-1-indenyl)zirconium dichloride, PA1 rac-Dimethylsilylene-bis(2-methyl-4-(m-tolyl)-1-indenyl)zirconium dichloride, PA1 rac-Dimethylsilylene-bis(2-methyl-4-(o-tolyl)-1-indenyl)zirconium dichloride, PA1 rac-Dimethylsilylene-bis(2-methyl-4-(o,o'-dimethylphenyl)-1-indenyl)zirconi um dichloride, PA1 rac-Dimethylsilylene-bis(2-methyl-4-(p-ethylphenyl)-1-indenyl)zirconium dichloride, PA1 rac-Dimethylsilylene-bis(2-methyl-4-(p-i-propylphenyl)-1-indenyl)zirconium dichloride, PA1 rac-Dimethylsilylene-bis(2-methyl-4-(p-benzylphenyl)-1-indenyl)zirconium dichloride, PA1 rac-Dimethylsilylene-bis(2-methyl-4-(p-biphenyl)-1-indenyl)zirconium dichloride, PA1 rac-Dimethylsilylene-bis(2-methyl-4-(m-biphenyl)-1-indenyl)zirconium dichloride, PA1 rac-Dimethylsilylene-bis(2-methyl-4-(p-trimethylsilylphenyl)-1-indenyl)zirc onium dichloride, PA1 rac-Dimethylsilylene-bis(2-methyl-4-(m-trimethylsilylphenyl)-1-indenyl)zirc onium dichloride, PA1 rac-Dimethylsilylene-bis(2-ethyl-4-phenyl-1-indenyl)zirconium dichloride, PA1 rac-Diphenylsilylene-bis(2-ethyl-4-phenyl-1-indenyl)zirconium dichloride, PA1 rac-Dimethylsilylene-bis(2-phenyl-4-phenyl-1-indenyl)zirconium dichloride, PA1 rac-Dimethylsilylene-bis(2-n-propyl-4-phenyl-1-indenyl)zirconium dichloride, PA1 rac-Diethylsilylene-bis(2-methyl-4-phenyl-1-indenyl)zirconium dichloride, PA1 rac-Di-(i-propyl)silylene-bis(2-methyl-4-phenyl-1-indenyl)zirconium dichloride, PA1 rac-Di-(n-butyl)silylene-bis(2-methyl-4-phenyl-1-indenyl)zirconium dichloride, PA1 rac-Dicyclohexylsilylene-bis(2-methyl-4-phenyl-1-indenyl)zirconium dichloride, PA1 rac-Methylphenylsilylene-bis(2-methyl-4-phenyl-1-indenyl)zirconium dichloride, PA1 rac-Diphenylsilylene-bis(2-methyl-4-phenyl-1-indenyl)zirconium dichloride, PA1 rac-Di(p-tolyl)silylene-bis(2-methyl-4-phenyl-1-indenyl)zirconium dichloride, PA1 rac-Di(p-chlorophenyl)silylene-bis(2-methyl-4-phenyl-1-indenyl)zirconium dichloride, PA1 rac-Methylene-bis(2-methyl-4-phenyl-1-indenyl)zirconium dichloride, PA1 rac-Ethylene-bis(2-methyl-4-phenyl-1-indenyl)zirconium dichloride, PA1 rac-Dimethylgermylene-bis(2-methyl-4-phenyl-1-indenyl)zirconium dichloride, PA1 rac-Dimethylstannylene-bis(2-methyl-4-phenyl-1-indenyl)zirconium dichloride, PA1 rac-Dimethylsilylene-bis(2-methyl-4-phenyl-1-indenyl)zirconium dibromide, PA1 rac-Dimethylsilylene-bis(2-methyl-4-phenyl-1-indenyl)zirconium dimethyl, PA1 rac-Dimethylsilylene-bis(2-methyl-4-phenyl-1-indenyl)zirconium methylchloride, PA1 rac-Dimethylsilylene-bis(2-methyl-4-phenyl-1-indenyl)zirconium chloride SO.sub.2 Me, and PA1 rac-Dimethylsilylene-bis(2-methyl-4-phenyl-1-indenyl)zirconium chloride OSO.sub.2 Me. PA1 (1) An organoaluminum compound such as trialkylaluminum is added to an aromatic hydrocarbon solvent suspension of a compound containing adsorbed water or a salt containing water of crystallization, e.g., magnesium chloride hydrate, copper sulfate hydrate, aluminum sulfate hydrate, nickel sulfate hydrate or cerous chloride hydrate, to thereby allow the organoaluminum compound to react with the adsorbed water or the water of crystallization, followed by recovering aluminoxane as its aromatic hydrocarbon solvent solution. PA1 (2) Water, ice or water vapor is allowed to directly act on an organoaluminum compound such as trialkylaluminum in a medium such as benzene, toluene, ethyl ether or tetrahydrofuran, followed by recovering aluminoxane as its aromatic hydrocarbon solvent solution. PA1 (3) An organotin oxide such as dimethyltin oxide or dibutyltin oxide is allowed to react with an organoaluminum compound such as trialkylaluminum in a hydrocarbon medium such as decane, benzene or toluene. PA1 salts of anions, such as bis[tri(n-butyl)ammonium]nonaborate and bis[tri(n-butyl)ammonium]decaborate; and PA1 salts of metallic borane anions, such as tri(n-butyl)ammoniumbis(dodecahydridododecaborate)cobaltate(III) and bis[tri(n-butyl)ammonium]bis(dodecahydridododecaborate)-nickelate(III). PA1 salts of metallic carborane anions, such as tri(n-butyl)ammoniumbis(nonahydrido-1,3-dicarbanonaborate)cobaltate(III) and tri(n-butyl)ammoniumbis(undecahydrido-7,8-dicarbaundecaborate)ferrate(III) PA1 trialkylaluminums, such as trimethylaluminum, triethylaluminum, triisopropylaluminum, tri-n-butylaluminum, triisobutylaluminum and tri-sec-butylaluminum; PA1 alkenylaluminums represented by the formula (i-C.sub.4 H.sub.9).sub.X Al.sub.y (C.sub.5 H.sub.10)z (wherein x, y and z are each a positive number, and z.gtoreq.2x), such as isoprenylaluminumi; PA1 dialkylaluminum halides, such as dimethylaluminum chloride and diisobutylaluminum chloride; PA1 dialkylaluminum hydrides, such as diisobutylaluminum hydride; PA1 dialkylaluminum alkoxides, such as dimethylaluminum methoxide; and PA1 dialkylaluminum aryloxides, such as diethylaluminum phenoxide. PA1 a composition comprising the modified copolymer in an amount of 10 to 80 parts by weight, preferably 30 to 80 parts by weight, and the ethylene/.alpha.-olefin copolymer in an amount of 20 to 90 parts by weight, preferably 20 to 70 parts by weight, with the proviso that the total amount of the copolymers is 100 parts by weight; PA1 a composition comprising the modified copolymer in an amount of 10 to 80 parts by weight, preferably 30 to 80 parts by weight, and the ethylene/vinyl acetate copolymer in an amount of 20 to 90 parts by weight, preferably 20 to 70 parts by weight, with the proviso that the total amount of the copolymers is 100 parts by weight; and PA1 a composition comprising the modified copolymer in an amount of 10 to 80 parts by weight, preferably 30 to 80 parts by weight, the ethylene/.alpha.-olefin copolymer in an amount of 5 to 60 parts by weight, preferably 10 to 50 parts by weight, and the ethylene/vinyl acetate copolymer in an amount of 5 to 40 parts by weight, preferably 10 to 30 parts by weight, with the proviso that the total amount of the copolymers is 100 parts by weight.
The laminate disclosed in the above publication comprises a polyester or polycarbonate layer, an intermediate layer formed from the above-mentioned adhesive resin composition and a saponified olefin/vinyl acetate copolymer layer.
Though the adhesive resin composition mentioned above has excellent adhesion properties at ordinary temperature after high-temperature treatment, the laminate using the composition occasionally suffers separation of layers when it is subjected to hot filling treatment or retorting treatment.
Accordingly, there has been desired development of adhesive resin compositions by the use of which layer-separation of laminates can be inhibited even when the laminates are subjected to hot filling treatment or retorting treatment.
It is an object of the present invention to provide an adhesive resin composition which can keep practical adhesive strength at ordinary temperature after high-temperature treatment and has excellent thermoresistance adhesion properties at high temperatures so that layer-separation of a laminate using the composition can be inhibited when the laminate is subjected to severe treatment such as hot filling treatment or retorting treatment.
It is another object of the invention to provide a laminate which comprises a polycarbonate or polyester resin layer, a layer of the above-mentioned adhesive resin composition as an adhesive layer and a saponified ethylene/vinyl acetate copolymer layer, and which has excellent gas permeation resistance and is free from separation of layers when subjected to hot filling treatment or retorting treatment.